[The human control of atomic energy could] virtually provide anyone who wanted it with a private sun of his own.

[What verdict would a historian of the year 3000 pass upon our age? Let us hope this will be his judgement:]
“The twentieth century was, without question, the most momentous hundred years in the history of Mankind. It opened with the conquest of the air, and before it had run half its course had presented civilisation with its supreme challenge—the control of atomic energy. Yet even these events, each of which changed the world, were soon to be eclipsed. To us a thousand years later, the whole story of Mankind before the twentieth century seems like the prelude to some great drama, played on the narrow strip of stage before the curtain has risen and revealed the scenery. For countless generations of men, that tiny, crowded stage—the planet Earth—was the whole of creation, and they the only actors. Yet towards the close of that fabulous century, the curtain began slowly, inexorably to rise, and Man realised at last that the Earth was only one of many worlds; the Sun only one among many stars. The coming of the rocket brought to an end a million years of isolation. With the landing of the first spaceship on Mars and Venus, the childhood of our race was over and history as we know it began….”

Atomic energy bears that same duality that has faced man from time immemorial, a duality expressed in the Book of Books thousands of years ago: “See, I have set before thee this day life and good and death and evil … therefore choose life.”

Human civilization is but a few thousand years long. Imagine having the audacity to think that we can devise a program to store lethal radioactive materials for a period of time that is longer than all of human culture to date.

In answer to the question, “Was the development of the atomic bomb by the United States necessary?” I reply unequivocally, “Yes.” To the question, “Is atomic energy a force for good or for evil?” I can only say, “As mankind wills it.”

In the years since man unlocked the power stored up within the atom, the world has made progress, halting, but effective, toward bringing that power under human control. The challenge may be our salvation. As we begin to master the destructive potentialities of modern science, we move toward a new era in which science can fulfill its creative promise and help bring into existence the happiest society the world has ever known.

It is probable that all heavy matter possesses—latent and bound up with the structure of the atom—a similar quantity of energy to that possessed by radium. If it could be tapped and controlled, what an agent it would be in shaping the world's destiny! The man who puts his hand on the lever by which a parsimonious nature regulates so jealously the output of this store of energy would possess a weapon by which he could destroy the Earth if he chose.
A prescient remark on atomic energy after the discovery of radioactivity, but decades before the harnessing of nuclear fission in an atomic bomb became a reality.

It was not until 1901 that humanity knew that nuclear energy existed. It is understandable now—but useless—to wish that we still lived in the ignorance of 1900.

Mankind has always drawn from outside sources of energy. This island was the first to harness coal and steam. But our present sources stand in the ratio of a million to one, compared with any previous sources. The release of atomic energy will change the whole structure of society.

No scientific subject has ever aroused quite the same mixture of hopes and fears [as atomic energy].

Personally I think there is no doubt that sub-atomic energy is available all around us, and that one day man will release and control its almost infinite power. We cannot prevent him from doing so and can only hope that he will not use it exclusively in blowing up his next door neighbour. (1936)

Should the research worker of the future discover some means of releasing this [atomic] energy in a form which could be employed, the human race will have at its command powers beyond the dream of scientific fiction, but the remotest possibility must always be considered that the energy once liberated will be completely uncontrollable and by its intense violence detonate all neighbouring substances. In this event, the whole of the hydrogen on earth might be transformed at once and the success of the experiment published at large to the universe as a new star.

Suddenly there was an enormous explosion, like a violent volcano. The nuclear reactions had led to overheating in the underground burial grounds. The explosion poured radioactive dust and materials high up into the sky. It was just the wrong weather for such a tragedy. Strong winds blew the radioactive clouds hundreds of miles away. It was difficult to gauge the extent of the disaster immediately, and no evacuation plan was put into operation right away. Many villages and towns were only ordered to evacuate when the symptoms of radiation sickness were already quite apparent. Tens of thousands of people were affected, hundreds dying, though the real figures have never been made public. The large area, where the accident happened, is still considered dangerous and is closed to the public.

That atomic energy though harnessed by American scientists and army men for destructive purposes may be utilised by other scientists for humanitarian purposes is undoubtedly within the realm of possibility. … An incendiary uses fire for his destructive and nefarious purpose, a housewife makes daily use of it in preparing nourishing food for mankind.

The Dark Ages may return—the Stone Age may return on the gleaming wings of Science; and what might now shower immeasureable material blessings upon mankind may even bring about its total destruction. Beware! I say. Time may be short.
Referring to the discovery of atomic energy.

The energy produced by the breaking down of the atom is a very poor kind of thing. Anyone who expects a source of power from transformation of these atoms is talking moonshine. … We hope in the next few years to get some idea of what these atoms are, how they are made, and the way they are worked.

The idea of atomic energy is illusionary but it has taken so powerful a hold on the minds, that although I have preached against it for twenty-five years, there are still some who believe it to be realizable.

The key to the utilization of atomic energy for world peace will be found in the will of all people to restrict its use for the betterment of mankind.

The major gift of science to the world is a mighty increase of power. Did science then create that power? Not a bit of it! Science discovered that power in the universe and set it free. Science found out the conditions, fulfilling which, the endless dynamic forces of the cosmos are liberated. Electricity is none of man’s making, but man has learned how to fulfill the conditions that release it. Atomic energy is a force that man did not create, but that some day man may liberate. Man by himself is still a puny animal; a gorilla is much the stronger. Man's significance lies in another realm—he knows how to fulfill conditions so that universal power not his own is set free. The whole universe as man now sees it is essentially a vast system of power waiting to be released.

The pace of science forces the pace of technique. Theoretical physics forces atomic energy on us; the successful production of the fission bomb forces upon us the manufacture of the hydrogen bomb. We do not choose our problems, we do not choose our products; we are pushed, we are forced—by what? By a system which has no purpose and goal transcending it, and which makes man its appendix.

The release of atomic energy has not created a new problem. It has merely made more urgent the necessity of solving an existing one … I do not believe that civilization will be wiped out in a war fought with the atomic bomb. Perhaps two thirds of the people of the Earth would be killed.

The terror of the atom age is not the violence of the new power but the speed of man’s adjustment to it—the speed of his acceptance.

Typical of the fundamental scientific problems whose solution should lead to important industrial consequences are, for example, the release of atomic energy, which experiment has shown to exist in quantities millions of times greater than is liberated by combustion.

We are dabbling in what will always be considered the blackest of black magic. The day will come when people will want to string us up from the nearest lamppost.
His first remark at the first meeting of the Reactor Safety Committee of the Atomic Energy Commission (1947).

We may have to live with the failure to control atomic energy for the rest of our lives. If that is to be our lot, let us face it steadfastly with faith in the civilisation we defend. The acid test of the strength of our society is the self-discipline of its adherents.